Process Statistics header, add max RSS to render_pdfs

tools/ProcStats.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "ProcStats.h"
+
+#if defined(SK_BUILD_FOR_UNIX) || \
+    defined(SK_BUILD_FOR_MAC) || \
+    defined(SK_BUILD_FOR_ANDROID)
+
+    #include <sys/resource.h>
+    int sk_tools::getMaxResidentSetSizeKB() {
+        struct rusage ru;
+        getrusage(RUSAGE_SELF, &ru);
+    #if defined(SK_BUILD_FOR_MAC)
+        return static_cast<int>(ru.ru_maxrss / 1024);  // Darwin reports bytes.
+    #else
+        return static_cast<int>(ru.ru_maxrss);  // Linux reports kilobytes.
+    #endif
+    }
+
+#else
+
+    int sk_tools::getMaxResidentSetSizeKB() {
+        return -1;
+    }
+
+#endif